Improve error message when changing global document flag.

2 files changed, 7 insertions, 3 deletions

diff --git a/config-model/src/main/java/com/yahoo/vespa/model/application/validation/change/GlobalDocumentChangeValidator.java b/config-model/src/main/java/com/yahoo/vespa/model/application/validation/change/GlobalDocumentChangeValidator.java
index 73bf3a4fe3e..198030d1f44 100644
--- a/config-model/src/main/java/com/yahoo/vespa/model/application/validation/change/GlobalDocumentChangeValidator.java
+++ b/config-model/src/main/java/com/yahoo/vespa/model/application/validation/change/GlobalDocumentChangeValidator.java
@@ -41,8 +41,10 @@ public class GlobalDocumentChangeValidator implements ChangeValidator {
                 boolean currentIsGlobal = currentCluster.isGloballyDistributed(currentDocumentType);
                 boolean nextIsGlobal = nextCluster.isGloballyDistributed(nextDocumentType);
                 if (currentIsGlobal != nextIsGlobal) {
-                    throw new IllegalStateException(String.format("Document type %s in cluster %s changed global from %s to %s",
-                            documentTypeName, clusterName, currentIsGlobal, nextIsGlobal));
+                    throw new IllegalStateException(String.format("Document type %s in cluster %s changed global from %s to %s. " +
+                                    "Add validation override '%s' to force this change through. " +
+                                    "First, stop services on all content nodes. Then, deploy with validation override. Finally, start services on all content nodes.",
+                            documentTypeName, clusterName, currentIsGlobal, nextIsGlobal, ValidationId.globalDocumentChange.value()));
                 }
             }
         });
diff --git a/config-model/src/test/java/com/yahoo/vespa/model/application/validation/change/GlobalDocumentChangeValidatorTest.java b/config-model/src/test/java/com/yahoo/vespa/model/application/validation/change/GlobalDocumentChangeValidatorTest.java
index bc6863c9a7c..68b21222fc5 100644
--- a/config-model/src/test/java/com/yahoo/vespa/model/application/validation/change/GlobalDocumentChangeValidatorTest.java
+++ b/config-model/src/test/java/com/yahoo/vespa/model/application/validation/change/GlobalDocumentChangeValidatorTest.java
@@ -40,7 +40,9 @@ public class GlobalDocumentChangeValidatorTest {
             assertTrue(allowed);
         } catch (IllegalStateException e) {
             assertFalse(allowed);
-            assertEquals("Document type music in cluster default changed global from " + oldGlobal + " to " + newGlobal,
+            assertEquals("Document type music in cluster default changed global from " + oldGlobal + " to " + newGlobal + ". " +
+                    "Add validation override 'global-document-change' to force this change through. " +
+                    "First, stop services on all content nodes. Then, deploy with validation override. Finally, start services on all content nodes.",
                     e.getMessage());
         }
     }